package com.alibaba.jstorm.message.netty;

import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.buffer.ChannelBufferOutputStream;
import org.jboss.netty.buffer.ChannelBuffers;


enum ControlMessage {
    CLOSE_MESSAGE((short) -100),
    EOB_MESSAGE((short) -201),
    OK_RESPONSE((short) -200),
    FAILURE_RESPONSE((short) -400);

    private short code;


    // private constructor
    private ControlMessage(short code) {
        this.code = code;
    }


    /**
     * Return a control message per an encoded status code
     * 
     * @param encoded
     * @return
     */
    static ControlMessage mkMessage(short encoded) {
        for (ControlMessage cm : ControlMessage.values()) {
            if (encoded == cm.code)
                return cm;
        }
        return null;
    }


    int encodeLength() {
        return 2; // short
    }


    /**
     * encode the current Control Message into a channel buffer
     * 
     * @throws Exception
     */
    ChannelBuffer buffer() throws Exception {
        ChannelBufferOutputStream bout =
                new ChannelBufferOutputStream(ChannelBuffers.directBuffer(encodeLength()));
        write(bout);
        bout.close();
        return bout.buffer();
    }


    void write(ChannelBufferOutputStream bout) throws Exception {
        bout.writeShort(code);
    }
}
